In Waddaï province, Eastern Chad, the dry tropical climate of the Sahel region causes a scarcity of surface water resources in the area. To respond to the growing demand on this vital element, and to preserve the social, economic and political stability, several groundwater (GW) exploration programs have been conducted in the previous decades. Of the few thousands of boreholes executed at the province of Waddaï, most fail to find GW reservoirs due to a lack of GW potential maps. In this study we try to fill this knowledge gap using Frequency Ratio (FR) and Weight of Evidence (WoE) techniques. The position of successful wells was used to train the statistical analysis methods and validate the models, while a total of nine topographic, geological and environmental factors were chosen as predictive variables. Results showed that the Southern and central parts of the province have greater potential for the presence of GW. This disposition was shown to be mainly controlled by lithology and slope, where flat areas dominated by unconsolidated alluvial deposits favour infiltration while rocky steep terrains favour surface flow. In comparison to the only previous study recently published, which used and expert opinion Multi-Criteria Decision-Making and Analytical Hierarchical Process based approach for the same purposes, some contradictions with the FR and WoE were observed in some predictive variable class weights, especially regarding lineament density and drainage density. This shows that, in areas where hydrogeological mechanisms and processes are not well understood, it is risky to rely on theoretical simplifying assumptions which are not always true.